Effects of deposition power of IGZO film and graphene layer in IGZO/graphene + Ni/SiO2/Si wafer specimens on the mechanical and electrical properties

In the present study, indium gallium zinc oxide (IGZO) films were deposited onto graphene + Ni/SiO2/Si wafer specimens with deposition powers of 60-, 80-, and 100-W, respectively. The effects of deposition power on the microstructure and vacancy defects formed in the graphene + Ni layer are evaluated based on the electrical and mechanical properties of as-received specimens. The role and behavior of the graphene + Ni film on the electrical resistance of the IGZO film with microcracks were evaluated using a tribotester. The variations of the acceleration, ay, in the direction normal to specimen contact surface and the morphology of worn surface and the friction coefficient in a stroke are provided us to identify their wear styles including seizure, stick-slip motion, and running-in instability. After applying a number of swing cycles, the turning angle of the Ni crystalline with respect to the graphene orientation increases with increasing the number of cycles. The mean microcrack length increases with increasing the turning angle. However, the electrical resistance of specimen is not elevated by increasing the microcrack length so long as the connection of the graphene layer with the IGZO film is sustained. Increase in the deposition power promotes the growth of hillocks in the graphene + Ni layer. These hillocks make the graphene + Ni layer convex with an uneven film thickness and lead to void defects in the graphene + Ni layer, they also cause the IGZO film with relatively large mean surface roughness and high friction coefficient.

Link: 

https://www.sciencedirect.com/science/article/pii/S0257897217301652